Liquid pressure transfer printing method of steering wheel rim for automobile and masking tape cutting apparatus used therefor

ABSTRACT

A steering wheel rim ( 22 ) for an automobile by using a liquid pressure transfer printing methods is manufactured by attaching masking tape ( 18 ) to a boudary portion of the steering wheel rim to be separately transfer-printed, marking a conjunction line ( 8   a ) by using a blade ( 25 ) in the middle portion the masking tape and detaching a lower half portion of the masking tape, covering an upper portion of the masking tape, performing transfer printing a surface lower than the conjunction line and cleaning and drying the transfer-printed surface and removing the masking tape and a protective masking tape ( 18   c ), secondly attaching another masking tape to a first transfer printing boundary portion of the steering wheel rim, marking a separation line ( 8   b ) by using a blade at a position about 0.05-0.2 mm lower than the conjunction line and removing the upper half of the protective masking tape, covering the lower portion of the masking tape and the lower portion of the masking tape with a protective masking tape, and after secondly performing transfer printing on an upper surface of the conjunction line and cleaning and drying the transfer-printed surface, removing the masking tape and the protective masking tape. Also, a cutting apparatus for performing the above steps includes a horizontal rotary pedestal ( 20 ) on which the steering wheel rim is placed, a clamp ( 23 ) for fixing the steering wheel lamp, and a blade holder ( 24 ) for marking a cut line at a uniform height.

TECHNICAL FIELD

[0001] The present invention relates to a method for manufacturing asteering wheel rim for an automobile by using a liquid pressure transferprinting method and an apparatus for cutting a masking tape usedtherefor, and more particularly, to a method for manufacturing asteering wheel rim for an automobile by using a liquid pressure transferprinting method, in which a masking tape is used in a matching processof a combination portion by a PVA solution when separate transferprinting is formed due to a limit in shape of an object subject totransfer printing so that environmental pollution is minimized due toreduction in the amount of waste water and productivity and reliabilityof products are improved, and an apparatus for cutting a masking tapeused therefor.

BACKGROUND ART

[0002] Techniques of printing various patterns on a surface of asteering wheel rim for an automobile by using a liquid pressure transferprinting method have been suggested in Korean Patent Application Nos.17425, 36990 and 36991 filed by the present applicant in 1998.

[0003] Also, to improve and automate the above suggested techniques, thepresent applicant filed Korean Patent Application No. 3368 in 1999 andKorean Patent Application No. 11606 in 1999 as a technique for matchingcombination of patterns.

[0004] In Korean Patent Application Nos. 36990 and 36991 filed in 1998,as shown in FIG. 1, since a first mask member 8 and a conjunction line 8a in the middle must be accurately matched, and after a first transferprinting is performed on a surface a that is a portion which is notmasked, a second masking must be accurately performed with an intervalof about 0.1 mm from the conjunction line in the middle, an accuratetransfer printing work at a boundary surface is very difficult andmanufacturing productivity is deteriorated due to a slow work speed.Furthermore, such difficulties have been a factor in the increase of thecost.

[0005] Also, since the entire surface subject to transfer printing aremasked in the first and second steps, the masking tape is wasted.Further, according to a degree of skill of a worker, the conjunctionline 81 in the middle is not matched so that infective products areoften generated.

[0006] Also, the technique disclosed in Korean Patent Application No.17425 filed by the present applicant in 1998 is a method in whichmasking tape and PVA solution are used. In FIG. 1, when the first maskmember 8 is attached, tiny pores are generated in a transfer film at acombination portion, forming a non transfer-printing strip due to thethickness of the masking tape during the second transfer printing step.To overcome the above problem, an edge portion located at theconjunction line 8 a in the middle of the masking tape 18, that is, theedge of the first mask member 8, is needed to be cut at an inclinationangle of about 60°. However, such cutting is difficult. Also, when thefirst mask member 8 is removed in the state in which PVA solution iscoated and dried after transfer printing is performed on the surface aand the surface is cleaned and dried, a PVA film is not uniformlyremoved and is unevenly lifted from the boundary surface so thatinfectiveness such as mismatch or overlap of transfer printing isgenerated.

[0007] Also, in Korean Patent Application No. 3368 filed by the presentapplicant in 1999, the masking tape and PVA solution are used togetherand a conjunction line in the middle of the masking tape issemiautomatically and uniformly processed by using a predetermined jig.

[0008] In the case of mass production by using the above method, aconsiderable time is needed for drying due to use of a large amount ofPVA solution. Accordingly, a drying equipment is additionally needed anda space for drying is needed. Also, a cleaning equipment for cleaningthe PVA solution is additionally needed. Further, a waste waterpurification equipment is needed due to an increase in the amount ofcleaning. When conditions for drying are not proper after the PVAsolution is coated, the conjunction line is incorrect and thus productsmay be defective. As a result, due to the above restrictions andproblems, the costs of products increase.

DISCLOSURE OF THE INVENTION

[0009] To solve the above problems, it is an objective of the presentinvention to provide a method for manufacturing a steering wheel rim foran automobile by using a liquid pressure transfer printing method bywhich mass production is possible by remarkably improving productivity,the cost for manufacturing a product is considerably reduced by adding aminimum equipment so that the existing equipment is effectively used ina limited space, the amount of waste water is sharply reduced so thatenvironmental pollution is reduced, and an unskilled worker can performan accurate pattern match on the boundary surface during separatetransfer printing regardless of conditions for drying, and an apparatusfor cutting a masking tape used therefor.

[0010] To accomplish the above object of the present invention, there isprovided a method for manufacturing a steering wheel rim for anautomobile by using a liquid pressure transfer printing method, whichcomprises the steps of attaching a masking tape having a predeterminedwidth to a boundary portion of the steering wheel rim to be separatelytransfer-printed, marking a conjunction line by using a blade in themiddle portion the masking tape attached on the steering wheel rim whichis placed on a horizontal rotary pedestal and detaching a lower halfportion of the masking tape, covering an upper portion of the maskingtape which is not detached with a protective masking tape, performingtransfer printing a surface lower than the conjunction line and cleaningand drying the transfer-printed surface, and removing the masking tapewhich is not detached and the protective masking tape covering the upperportion of the protective masking tape, secondly attaching a maskingtape having a predetermined width to a first transfer printing boundaryportion of the steering wheel rim to which transfer printing isperformed, marking a separation line by using a blade at a positionabout 0.05-0.2 mm lower than the conjunction line of the masking tapeattached to the steering wheel rim 22 which is placed on the horizontalrotary pedestal and removing the upper half of the protective maskingtape, covering the lower portion of the masking tape which is notremoved and the lower portion of the masking tape with a protectivemasking tape, and after secondly performing transfer printing on anupper surface of the conjunction line and cleaning and drying thetransfer-printed surface, removing the masking tape and the protectivemasking tape.

[0011] Also, to accomplish the above object of the present invention,there is provided an apparatus for cutting a masking tape used formanufacturing a steering wheel rim for an automobile by using a liquidpressure transfer printing method, which comprises a horizontal rotarypedestal which is rotatable and has a horizontally flat surface on whichthe steering wheel rim is closely placed, and a clamp provided at theside portion of the horizontal rotary pedestal to fix the steering wheelrim.

[0012] It is preferred in the present invention that a plurality ofblade holders are formed on the horizontal rotary pedestal, each havinga blade moving along the surface of the horizontal rotary pedestal sothat a cut line is marked at a predetermined height from the surface ofthe horizontal rotary pedestal.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013]FIG. 1 is perspective view showing portion of a steering wheel rimfor explaining the conventional liquid pressure transfer printingmethod;

[0014]FIG. 2 is a perspective view showing portion of a steering wheelrim in which the masking tape is attached and the conjunction line isformed;

[0015]FIG. 3 is a perspective view showing the structure of a maskingtape cutting apparatus according to a present invention;

[0016]FIG. 4 is a perspective view of portion of a steering wheel rim ina step of removing part of the masking tape;

[0017]FIG. 5 is a perspective view of portion of a steering wheel rim ina step of forming a separation line;

[0018]FIG. 6 is a perspective view of a blade holder set according tothe present invention; and

[0019]FIGS. 7A through 7I are views for sequentially showing the liquidpressure transfer printing method according to the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

[0020] Detailed steps in the present method and a cutting apparatus usedtherein are described with reference to the attached drawings.

[0021] One of the greatest features of the present invention is thatonly a masking tape is used without using PVA solution. That is, asshown in FIG. 2, for example of a steering wheel rim for an automobile,when a portion partially formed of hard urethane is subject to liquidtransfer printing, a masking tape 18 which is a strip having a width of4-5 mm is attached and the steering wheel rim is placed on an upperplate 21 of a horizontal rotary pedestal and fixed by a clamp 23, asshown in FIG. 3.

[0022] A blade holder 24 is disposed on the upper plate 21. A blade 25of which the height can be adjusted is installed at the blade holder 24.The height of the blade 25 may be adjusted by adopting a simplestructure in which a groove for accommodating the blade 25 is formed ina lengthwise direction of the blade holder 24 and the blade 25 is fixedor loosed by using a screw penetrating in a radial direction of theblade holder 24. In addition, various structures regardless of aparticular shape may be applied.

[0023] The blade 25 of the blade holder 24, like the left blade shown inFIG. 6, is fixed to a height of the conjunction line 8 a in the middleportion of the masking tape 18 which is indicated by a dotted line.

[0024] As shown in FIG. 3, in the state in which the steering wheel rim22 is fixed, the blade holder 24 is rotated around the outercircumference of the steering wheel rim 22 or the upper plate 21 isrotated while the blade holder 24 is manually held, to mark theconjunction line 8 a as indicated by a dotted line of FIG. 2. Then, asshown in FIG. 4, the masking tape 18 at the lower portion with respectto the conjunction line 8 a is separated. The step of detaching themasking tape 18 may be performed to the masking tape 18 at the innercircumference of the steering wheel rim 22.

[0025] After a separately prepared protective masking tape is attachedon a surface b as shown in FIG. 5, transfer printing is performed on asurface c which is under the surface b. After the transfer-printedsurface c is cleaned and dried, the masking tape 18 and the protectivemasking tape attached on the surface b are removed. Then, the maskingtape 18 is attached again in the middle of the steering wheel rim 22 ina lengthwise direction thereof, as shown in FIG. 4. The steering wheelrim 22 is flipped and placed on the upper plate 21 of the horizontalrotary pedestal 20 and is fixed by the clamp 23.

[0026] Here, the height of the blade 25 of the blade holder 24 is fixedat a height 0.05-0.2 mm lower than the middle conjunction line 8 a, likethe right blade shown in FIG. 6. Thus, a conjunction line 8 b is formedas indicated by a dotted line in FIG. 5.

[0027] The height adjustable blade 25 coupled to the blade holder 24 maybe adopted, or as shown in FIG. 6, two blade holders 24 fixed tomaintain a height difference between the blades 25 within a range of0.05-0.2 mm may be used. The upper portion of the separation line 8 b isremoved and then a protective masking tape is attached to a portionbelow the separation line 8 b. The surface b which is nottransfer-printed is secondly transfer-printed and cleaned and dried sothat a clean transfer printing can be performed forming a match aroundthe boundary line.

[0028] The above-described separate transfer printing steps aredescribed in order with reference to the drawings. First, as shown inFIG. 7A, the masking tape 18 having a predetermined width is attached inthe middle portion of the steering wheel rim 22 in a lengthwisedirection. The conjunction line 8 a is marked at around the middleportion of the masking tape 18 by using the blade 25. Next, as shown inFIG. 7B, the masking tape 8 a at the lower portion below the conjunctionline 8 a is removed, here, the reason of forming a conjunction line 8 aafter attaching the masking tape 18 having a predetermined width is toaccurately maintain a portion where the masking tape 18 is attached. Byperforming this step, an unskilled worker can easily perform a maskingwork at a non transfer printing portion.

[0029] After performing the above removing step, as shown in FIG. 7C,the protective masking tape 18 c is attached at the upper portion of theremaining masking tape 18. Then, a pattern is transfer-printed on alower surface of the protective masking tape 18 c and thetransfer-printed surface is cleaned and dried, as shown in FIG. 7D.Then, the protective masking tape 18 c at the upper portion of theprotective masking tape 18 c is removed. In the above transfer printingstep, a transfer printing film is attached at around the conjunctionline 8 a by being lifted due to a tiny width of the masking tape 18 sothat a non transfer-printed strip having a tiny width d is formed. Thefirst transfer printing boundary line 8 c maintains a state of notaccurately matching the conjunction line 8 a.

[0030] Continuously, the masking tape 18 is attached again at the firsttransfer-printed boundary portion, as shown in FIG. 7E. The separationline 8 b is formed at a position 0.05-0.2 mm below the conjunction line8 a, as shown in FIG. 7F. Here, the separation line 8 b is located to beslightly lower than the first transfer printing boundary line 8 c.

[0031] Next, as shown in FIG. 7G, the upper portion of the masking tape18 with respect to the separation line 8 b. A protective masking tape 18d is attached on a portion below the separation line 8 b, as shown inFIG. 7H. In the state in which the steering wheel rim 22 is flipped, apattern is secondly transfer-printed on the upper portion of theseparation line 8 b, that is, a non transfer-printed portion, as shownin FIG. 7I, and the transfer-printed portion is cleaned and dried. Theprotective masking tape 18 d and the remaining masking tape 18 areremoved so that all the steps are completed. Here, considering a nontransfer-printed strip formed due to the thickness of the masking tape18, since the first transfer printing boundary line 8 c is in a state offurther covering the surface of the steering wheel rim than the boundaryline of the masking tape 18 at the separation line 8 b as much as thewidth of the non transfer-printed portion, when the protective maskingtape 18 d and the masking tape 18 are removed, transfer printing isperformed in a completely matching state without a portion where theconjunction portion is overlapped or a non transfer-printed portion.

[0032] Industrial Applicability

[0033] According to the present invention, a masking tape is used in amatching process of a combination portion by a PVA solution whenseparate transfer printing is formed due to a limit in shape of anobject subject to transfer printing so that environmental pollution isminimized due to reduction in the amount of waste water. Accordingly,since a minimum equipment is added, the efficiency in use of theexisting equipment within a limited space is improved so that anadditional cost for a large scale of equipment is not needed. Thus,productivity can be remarkably improved and the manufacturing cost ofproducts is greatly reduced.

[0034] Further, by performing transfer printing twice, even an unskilledworker can perform an accurate pattern match on the boundary surfaceregardless of conditions for drying. Thus, reliability of products isimproved.

What is claimed is:
 1. A method for manufacturing a steering wheel rimfor an automobile by using a liquid pressure transfer printing method,the method comprising the steps of: attaching a masking tape having apredetermined width to a boundary portion of the steering wheel rim tobe separately transfer-printed; marking a conjunction line by using ablade in the middle portion the masking tape attached on the steeringwheel rim which is placed on a horizontal rotary pedestal and detachinga lower half portion of the masking tape; covering an upper portion ofthe masking tape which is not detached with a protective masking tape;performing transfer printing a surface lower than the conjunction lineand cleaning and drying the transfer-printed surface, and removing themasking tape which is not detached and the protective masking tapecovering the upper portion of the protective masking tape; secondlyattaching a masking tape having a predetermined width to a firsttransfer printing boundary portion of the steering wheel rim to whichtransfer printing is performed; marking a separation line by using ablade at a position about 0.05-0.2 mm lower than the conjunction line ofthe masking tape attached to the steering wheel rim 22 which is placedon the horizontal rotary pedestal and removing the upper half of theprotective masking tape; covering the lower portion of the masking tapewhich is not removed and the lower portion of the masking tape with aprotective masking tape; and after secondly performing transfer printingon an upper surface of the conjunction line and cleaning and drying thetransfer-printed surface, removing the masking tape and the protectivemasking tape.
 2. An apparatus for cutting a masking tape used formanufacturing a steering wheel rim for an automobile by using a liquidpressure transfer printing method, the apparatus comprising: ahorizontal rotary pedestal which is rotatable and has a horizontallyflat surface on which the steering wheel rim is closely placed; and aclamp provided at the side portion of the horizontal rotary pedestal tofix the steering wheel rim.
 3. The apparatus as claimed in claim 2,wherein a plurality of blade holders are formed on the horizontal rotarypedestal, each having a blade moving along the surface of the horizontalrotary pedestal so that a cut line is marked at a predetermined heightfrom the surface of the horizontal rotary pedestal.
 4. The apparatus asclaimed in claim 3, wherein two blade holders are formed as one set andone of the blades is formed to have a height of 0.05-0.2 mm lower thanthe other blade.